
\begin{tikzpicture}
  \def\Ax{2} \def\Ay{3} \def\Bx{0} \def\By{0} \def\Cx{6} \def\Cy{0}
  \coordinate[label=below:$B$] (B) at (\Bx,\By);
  \coordinate[label=below:$C$] (C) at (\Cx,\Cy);
  \coordinate[label=above:$A$] (A) at (\Ax,\Ay);
  \coordinate[label=below:$P$] (P)
    at ({\calcbisectorx\Bx\By\Ax\Ay\Cx\Cy},
      {\calcbisectory\Bx\By\Ax\Ay\Cx\Cy});
  \pic[mark angle={red}{5mm}{1.2}] {angle=B--A--C};
  \draw (A) -- (B) -- (C) -- cycle (A) -- (P);
\end{tikzpicture}
